Composite formwork for casting structural bodies



DEC 22 1964 K. sPElDEL 3,161,939

COMPOSITE RoRMwoRK FoR CASTING STRUCTURAL BODIES Filed Sept. 18, 1961 3Sheets-Sheet l A kul l/f Dec. 22, 1964 K. sPElDEL 3,161,939

COMPOSITE FORMWORK FOR CASTING STRUCTURAL. BODIES Filed Sept. 18, 1961 3Sheets-Sheet 2 Dec. 22, 1964 v K. sPElDEL 3,161,939

COMPOSITE FORMWORK FOR CASTING STRUCTURAL BODIES Filed Sept. 18, 1961 5Sheets-Sheet 3 /NVENOP 3,161,939 CMEBQSHE FRBJIWRK FR {ASTENGSfRUi'ITURlL BGDll Karl Speidel, Kupferzell, Wurtteniherg, fermany,assigner to Futura Ghibli., Glarus, Switzerland, a corporation ofSwitzeriand Filed Sept.. liti, wel, Ser. No. 138,676 Claims priority,application Germany fan. 25, i961 Claims. (Si. -131) My inventionrelates to formwork for casting structural bodies, preferably fromconcrete, in which the form or shutter panels, on the side remote fromthe concrete, are provided with stiifening means such as ribs or thelike, and with means for attachment of adjacent panels.

It has hitherto been customary to make wooden formwork from individualboards which are cut to shape and then nailed together. This isexpensive and time consuming, particularly since such forms are subjectto wear, for example due to weathering. To obviate these disadvantages,forms of sheet steel have been developed, in which plates of steel areconnected together by detachable connecting means. Such steel formwork,however, is also expensive, and inconveniently heavy, and has thefurther disadvantage of air-tightly covering the moist concrete, so thatthe concrete has no chance to dry.

It is an object of my invention to provide formwork which combines theadvantage of the known steel forms and the known wood forms withoutentailing the disadvantages of either and which, in particular, isprovided with ribs like those of the steel plate formwork to impartgreat stability to the assembled form structure. Another object is toprovide such reinforced formwork that can be assembled rapidly andaccurately in a simple manner.

According to the invention, l compose the formwork, to be used forcasting structural bodies, particularly of concrete, form individualpanel units having ribs or the like reinforcing means and means forattachment of adjacent panel units arranged on the side remote from theconcrete, and I provide each such panel unit with reference abutmentswhich slightly project over the edges of the panel, these referenceabutments being disposed at the corners of a rectangle or polygon insuch a manner that a number of the panel units may easily be assembledin vertical and horizontal rows by means of such reference abutments.

According to another, preferred feature of the invention, the referenceabutments are formed by longitudinal and transverse ribs which are fixedto the rear of each panel and constitute the above-mentioned reinforcingmeans, these reference abutments preferably having their abutment facesextend perpendicular to the plane of the panel.

According to a further feature of the invention, an accurate and firmconnection between the individual panel units of the formwork is securedby giving the reference abutments of the individual panel units the formof connecting elements, such as pins and bores, which lie transverselyto the ribs and parallel to each panel.

A jointless formwork is obtained, for example, from panels of laminatedwood or plywood having xed transverse and longitudinal reinforcing ribson the rear. Such panels, according to a further feature of myinvention, are treated, at least on the surface adjacent to theconcrete, with densifying substances such as phenol resins, urea resins,or by irnpregnating the surface with impregnated paper or the like, orby applying metal coating or by spraydepositing metals or syntheticresins. Such treatments impart great strength to the surface and make itresistant particularly to water.

Since the panel of laminated wood or plywood together with thereinforcing ribs of the rear surface form a single United States PatentO 'ice unit, the panel itself may be thin, thereby reducing the cost.The panel units can be given a particularly great strength by arrangingthe reinforcing ribs at equal distances from the edges of each panel,and accurately calculating the distances from the viewpoint of thestatic properties of the panel unit as a whole. The distance of eachlongitudinal rib from the respective adjacent edge of the panel ispreferably 0.21 times the width of the panel. The transverse ribs havethe same distance from the respective adjacent edges of the panel, sothat there is a central area bordered on all sides by the longitudinaland 'transverse ribs and having 0.58 times the Width and 9.42 times thelength of the panel. f

By arranging the longitudinal and transverse ribs in accordance with theinvention, the panels are subjected to a minimum of bending stressbecause, with a uniform distribution of the stress over the Whole panelsurface, the positive and negative bending moments will compensate eachother. The transverse ties protect the panel against unforeseenstresses. Formwork constructed in accordance with the invention consistsof jointless panel units which are easy to construct and inexpensive,and which can easily be assembled with adjacent panel units and havesatisfactory strength and the necessary permeability to water.

An embodiment of form panels -according to the invention is illustrated,by way of example, on the accompanying drawings, in which:

FIG. l is a top plan View of a standard panel unit of water-resistantglued plywood, the position of the transverse bars being indicated bybroken lines;

FlG. 2 is a section through the panel unit on the line ll-II of FIG. 1;y

FIGS. 3a and 3b are longitudinal sections through the panel unit on theline lll-III of FIG. 1;

FIG. 4 shows the ends of two adjacent ribs of two respective, adjacentpanel units connected by means of U- shaped clamping stirrups, theillustration being a longitudinal section through the ends of the ribs;

FIG. 5 is a section perpendicular to the plane of two connected panelunits, showing the adjacent ends of two ribs connected by means of acentral wedge key;

FiG. 6 is a section parallel to the plane of the panel units to show theconnection illustrated in FIG. 5; and

FIG. 7 is a partial top view of a formwork wall with one horizontal andtwo vertical rows of panel units, the figure serving particularly toindicate the arrangement of the reference abutments, the traverse barsbeing shown in broken lines and the connecting points by small circles.

The panel unit shown in FIG. l comprises a panel 2 to which are securedtwo parallel longitudinal ribs l and two transverse ribs 3. Overall, thepanel unit is preferably 1250 mm. long and 625 mm. wide, measuredbetween the two extreme ends of each longitudinal rib l. and eachtransverse rib 3 respectively. 'Ihe ends of the ribs l and 3 formrespective reference abutments D, D', C, C', E, E', F, F' which projectslightly over the edges of the panel 2. The measurements of the panel 2itself are preferably 1248 mm. by 623 mm. The panel'Z is thus set back,all around, fromV the abutment faces, i.e. the protruding ends of theribs, by an amount d, equal to about l mm. Due to this protrusion, onlythe confronting ends of the ribs come into contact when two adjacentpanel units are joined together, a gap of about 2 millimeters remainingbetween the adjacent edges of the panels 2 so that the protruding partsof the ribs 1, 3 provide abutting faces at their ends, for the relativelocation of adjacent panel units. Soiling of the edges of the panels 2does not, therefore, affect the accuracy ofthe dimensions of theprefabricated panel units, whereas soiling or darnaging of the abuttingyfaces of the ribs l, 3 is practically impossible, because these facesare tightly pressed against each other when the concrete is beingapplied. Instead of having .abutting faces which are perpendicular tothe plane of the panel and formed by the end -faces of the ribs 1 and 3,the reference -abutments D, C, E, vF may be obtained in some othermanner. For example, they may be formed -by connecting elements such aspins and bores disposed transversely to the ribs and parallel to thepanels.

By making the ratio between length and width of each panel unit 2:1, theunits may be arranged in more than one direction, las shown for examplein FIG. 7.

FIG. l shows, in detail, the ribs on the rear of the panel. Thelongitudinal or supporting ribs 1 are each arranged at a distance, lfromtheir respective edges of the panel 2, equal to about 0.21 of the tot-a1width B of the panel. Each of the transverse or stiening ribs 3 has thesarnev distance from its adjacent panel edge. Each of the eight rib endshas a U-shaped protective connecting cap 4, preferably of met-al, fixedto it to provide `the abut ting face. The abutting face of each cap ismachined, and extends in a plane at right angles to the longitudinalaxis of the respective rib. The abutting faces, which constitute the xedreference abutments D, D', C, C', E, E', F, F in accordance with theinvention, 4and which, as mentioned, project over the edges of the panelby about l mm. are disposed on an accurate imaginary rectangle. Thepanel units can, therefore, be assembled with great precision to producea formwork assembly which also is accurately rectangular. The inventiontherefore also affords the production of concrete structures of goodsurface appearance and is suitable at locations where it is exposed toview. Adjacent connecting caps 4 together form `a tension lock which canbe pressed -together by locking means and can be easily separated forremoving the panel units. v

According to a desirable feature of the invention, the distance of theribs 1, 3 from the respective edges of the panel is 0.21 times the widthofthe panel (FIG. l), which is particularly advantageous because thepositive and negative moments acting on the panel unit (assuming thestress due to the soft concre-te is uniformly distributed over the `areaof the panel) will be the same and will have the minimum value -for `abeam supported on two supports cantilevering at both ends. As aconsequence of this, Very thin panels 2 may be used to take up verylarge stressees.

If one considers the bending properties of the panel unit, a distance ofabout 0.23 of the width of the panel between the rib and the edge wouldbe preferable, but this would give the same results at the edge and inthe central area of the panel 2. Also Aapplicable is a distance of 0.25times the width of the panel between the ribs and the edges of thepanel. This would not be in accordance with static optimal conditions,but would afford staggering the panel units in two vertically adjacentrows, which in some cases results in attractive appearance from anarchitectural point of view.

FIG. 2 `shows a cross section through the panel unit, the longitudinalribs 1 being shown in section and the transverse rib 3 being shown inside elevation. It will be noted that the edges of the panel 2 are notquite ush with the connecting caps 4, but set back by the small amountd. The traverse bars 7 (FIGS. 2, 3) in this caseV are of the notchedtype. The notches accommodate steel tensioning rods S which act asconnecting elements for two panel ends in the form assembly in the caseof twosided wall formwork. Instead of a notched traverse bar, use may bemade of slotted traverse bars in which the distances between the slotscorrespond, like the distances f between the notches, to the width of astandard panel, because in each case the tensioning rods must lie innotches 6 (FIG. l) 'provided in the edges of the panels 2.

FIG. 3 is a longitudinal section through the panel unit so that thetransverse ribs 3 appear in section and a longitudinal rib 1 inelevation. Brackets 9 which hold the traverse Ibars 7 are attached bybolts 8. Each bracket 9 Ihas two hooks 8 which jointly straddle thelongitudinal rib 1. A lug 8" at the bottom of each bracket 9 holds it ata right angle to the rib 1. An alternative embodiment shown in the topportion of FIG. 3 has a bracket 9' which has a direct tighteningeffec-t, and which is cantilevered by an amount equal to the width ofthe traverse bar 7. The bracket 9 shown in the lower portion of thefigure is cantilevered outwards to a greater extent, and tightening iseffected by means of a T-shaped key Sia which is permanently fixed tothe bracket 9 and can be driven in parallel to the traverse bar 7. Thetensioning rods S are shown at the -top and bottom in FIG. 3.

FIG. 4 is a section showing two adjacent rib ends held together by awedging key which consists of a stirrup 1d pressing together with thetwo U-shaped connecting caps 4'. Each connecting cap i has a bore 11 toreceive the key. Lateral displacement of the key, and hence mis-.alignment of the rib ends, is prevented by a round-headed screw 12inthe center of one connecting cap and a corresponding recess 13 in theadjacent connecting cap (FIG. 4).

FIG. S is a section through a tightening lock which embodies a centralwedge. Semicircular profiles i4 are welded or otherwise xed in-to theconnecting caps 4. These proles `are enclosed by the iianks of aU-sectioned wedge key 15 which presses them together.

FG. '6 shows a section on the line IV-IV in FIG. 5 through the centralwedge "15 in the same direction as the section in FIG. 4. It shows theposition and functioning of the semicircular prole bodies 14 and thewedge 15 which is to be driven in from the side indicated by an arrow G.The forces exerted by the wedge 15 on the profile bodies 14 ,areindicated by arrows G1 and G2.

FIG. 7 shows a formwork wall with two vertical rows and one horizontalrow of panel units. As illustrated, one horizontal panel unit may easilybe connected with two vertical panel units, because the positions of theribs are correlated to one another. This ligure also shows the eightpoint system of the connections between the panels, and the positions ofthe traverse bar '7, which is indicated in broken lines. The notches 6,indicated as small circles, receive the tensioning rods. A number ofnon-standard or compensating panel units are shown at the right-handside for completion of the formwork to the desired dimensions. Two ofthese units have a width of Ms B, two have a width of Vs B and one has alength of 1%; L. These panels are indicated by the reference numerals2a, 2b, 2c.

The edges and corners of the panels may be specially protected asindicated at 5 (FIG. l), for example by sheet members of metal or hardpolyvinylchloride. This protective member may be in the form of apocket, which secures complete protection. Each of the longitudinalpanel edges, which may also be protected by proled coverings, isprovided with two of the above-mentioned recesses in the form of notches6, 6 to receive the connecting rod of the two halves of an adjacentpanel when the two panels are fitted together and the gap is closed.This rod is placed through the notches 6, 6 and connects the panel withthe traverse bar 7 on the rear side of the panel.

The positions of the recesses 6,6 are so chosen that their distancesfrom the adjacent edges of the panel are each 0.21 times the length ofthe panel. The traverse bar may be made of wood, metal or hard syntheticresin.

if desired, the reference abutments protruding over the panel edge maybe located on connecting lines which form geometrical figures other thanrectangles, for example right angles or isosceles triangles,parallelograms or the like. In certain cases, the ratio of the length tothe width of the panel may be other than 2:1, for example 4:1.

It will be understood that the other numerical values givenabove arelikewise intended as examples only. Thus, the longitudinal andtransverse ribs 1, 3 may be given a spacing from the edges of the panelsdilering from 0.21

arenoso times the width of the panels. For example, a very rigid panelunit, resistant to bending, is obtained by placing the longitudinal andtransverse ribs at a distance of 0.14 times the width of the panel awayfrom the panel edges. In this case, an additional transverse rib may beprovided in the middle of the iield formed by the mutually intersectinglongitudinal and transverse ribs.

Such and other modifications of formwork panel units according to theinvention will be obvious to those skilled in the art, upon a study ofthis disclosure, and it will therefore be apparent that the inventioncan be given embodiments other than particularly illustrated and dcribedherein, without departing from the essential features of my inventionand Within the scope of the claims annexed hereto.

I claim:

1. A composite formwork for casting structural bodies from hardeningmaterial such as concrete, comprising a number of individual panelunits, each having a front side to be contacted by the material to becast and having a rear side, each of said panels having reinforcingmeans and means for connection to adjacent panels arranged on the rearside, and having a plurality of reference abutments rigidly secured toeach of said panels and protruding slightly over each of the edges ofthe panel, said reference abutments having a thickness at leastsubstantially equal to the thickness of said panels, being located atthe rear side on the .corners of a regular geometric polygonal figureand having front sides respectively in ush abutment with correspondingfront sides of abutments of adjacent panels, whereby a number of thepanel units can be aligned and assembled in vertical and horizontal rowby means of said reference abutments, said panels in assembled conditiondefining a relatively thin intervening gap between portions of adjacentpanels, said abutments each protruding beyond the edges of the panels adistance half the width of said intervening gap, and clamping means forconnecting abutments of adjacent panels to retain said panels inadjacent assembled condition.

2. In a panel unit according to claim 1, said reinforcing meanscomprising longitudinal and transverse ribs fixed at the rear surfaceofthe panel, said abutments being the ends of respective ones of saidribs, said abutting faces being perpendicular to the panel surface.

3. In a panel unit according to claim 2, said longitudinal andtransverse ribs being each spaced the same distance from the respectiveadjacent edges of the panel equal to about 0.21 of the Width of thepanel.

4. A panel unit according to claim 2, comprising bolts which passthrough said longitudinal ribs, brackets for receiving traverse bars,each of said brackets having two fork-shaped hooks jointly straddlingone of said longitudinal ribs respectively and engaging said bolt whenmounted for suspending -said bracket therefrom, and said bracket havinga lug for xing the angular position of the bracket by engagement with'said longitudinal rib.

5. ln a panel unit according to claim 2, the thickness of said panel inaddition to the thickness of the longitudinal ribs being equal to thestandard thickness of a panelling plank or twice the thickness of apanelling board.

6. In a panel unit according to claim 1, said reinforcing meanscomprising longitudinal and transverse ribs of nonmetallic material,said ribsl having respective ends provided with protective metal caps,said caps constituting said abutments and having respective abutmentfaces protruding beyond the adjacent respective edges of said panel andextending at right angles to the yaxes of the respective ribs.

7. A formwork of panel units according to claim 6, comprising atightening lock consisting of U-shaped wedging stirrup, said caps of twoadjacent ribs having respective bores engageable by said stirrup and thestirrup being centraily located relative to the caps being connected,whereby said caps and panel units are tightened together by driving thestirrup into said bores, said stirrup being positioned at leastpartially within respective ribs being connected thereby.

8. In formwork of panel units according to claim 7, comprising a centralwedge key for fastening adjacent units to each other, said caps havingsemicircular proles, and said key being U-shaped and having its legsstraddle said proles for pressing them towards each other, said keybeing positioned at least partially within respective ribs beingconnected thereby.

9. In a panel unit according to claim 1, said abutments havingrespective machined abutting faces extending a predetermined `distanceover said panel edge with an accuracy within $0.2 millimeters.

Rater-ences Cited in the tile of this patent UNTED STATES PATENTS 76,672Sutherland Apr, 14, 1868 146,207 Schneider Jan; 6, 1874 213,520Mikkelson Mar. 25, 1879 953,383 Holman Mar. 29, 1910 1,540,570 RobertsJune 2, 1925 1,652,480 Hutchins Dec. 13, 1927 1,707,336 Venard Apr. 2,1929 2,017,553 Troiel Oct. 15, 1935 l2,236,616 Bosco Apr, 1, 19412,296,036 Horn Sept. 15, 1942 2,340,864 Carpenter Feb. 8, 1944 2,475,890Hamilton July 12, 1949 2,506,485 Boudcusquire May 2, 1950 2,522,360Hamilton Sept. 12, 1950 2,640,249 Symons June 2, 1953 2,698,536Robertson Jan. 4, 1955 2,859,503 Hennig Nov. 1l, 1958 2,948,046Immonetti Aug. 9, 1960 2,967,343 Williams Jan. 10, 1961

1. A COMPOSITE FORMWORK FOR CASTING STRUCTURAL BODIES FROM HARDENINGMATERIAL SUCH AS CONCRETE, COMPRISING A NUMBER OF INDIVIDUAL PANELUNITS, EACH HAVING A FRONT SIDE TO BE CONTACTED BY THE MATERIAL TO BECAST AND HAVING A REAR SIDE, EACH OF SAID PANELS HAVING REINFORCINGMEANS AND MEANS FOR CONNECTION TO ADJACENT PANELS ARRANGED ON THE REARSIDE, AND HAVING A PLURALITY OF REFERENCE ABUTMENTS RIGIDLY SECURED TOEACH OF SAID PANELS AND PROTRUDING SLIGHTLY OVER EACH OF THE EDGES OFTHE PANEL, SAID REFERENCE ABUTMENTS HAVING A THICKNESS AT LEASTSUBSTANTIALLY EQUAL TO THE THICKNESS OF SAID PANELS, BEING LOCATED ATTHE REAR SIDE ON THE CORNERS OF A REGULAR GEOMETRIC POLYGONAL FIGURE ANDHAVING FRONT SIDES RESPECTIVELY IN FLUSH ABUTMENT WITH CORRESPONDINGFRONT SIDES OF ABUTMENTS OF ADJACENT PANELS, WHEREBY A NUMBER OF THEPANEL UNITS CAN BE ALIGNED AND ASSEMBLED IN VERTICAL AND HORIZONTAL ROWBY MEANS OF SAID REFERENCE ABUTMENTS, SAID PANELS IN ASSEMBLED CONDITIONDEFINING A RELATIVELY THIN INTERVENING GAP BETWEEN PORTIONS OF ADJACENTPANELS, SAID ABUTMENTS EACH PROTRUDING BEYOND THE EDGES OF THE PANELS ADISTANCE HALF THE WIDTH OF SAID INTERVENING GAP, AND CLAMPING MEANS FORCONNECTING ABUTMENTS OF ADJACENT PANELS TO RETAIN SAID PANELS INADJACENT ASSEMBLED CONDITION.